THE Yankees’ two biggest stars didn’t act like friends the other night. Derek Jeter (above) and Alex Rodriguez, in Chicago to play the White Sox, both ended up at Sunda Asian restaurant Saturday night. “They sat at separate tables,” said one onlooker, “and didn’t speak to each other at all.” After Reggie Jackson stopped by both players’ tables to say hello, Jeter left and, “He gestured to A-Rod, but never said hi.” Reps for the Yankees did not respond to e-mails seeking comment.